Counter-balance door mechanism



July 17, 1934.

F. w. SCHEINEMAN ET AL 1,966,934 COUNTER BALANCE DOOR MECHANISM Filed May 21, 1951 2 Sheets-Sheet l July 17, 1934. F. w SCHEINEMAN m- AL 1,956,934

COUNTER BALANCE DOOR MECHANISM Filed May 21 1931 2 Sheets-Sheet 2 award,

JF ed J6 Patented July 17, 1934 STATES PATENT or ies 1,966,934 COUNTER-BALANCE noon MECHANISM Application May 21, 1931, Serial No. 539,029

Claims.

This invention relates to a counterbalance door mechanism and it pertains more particularly to a system for supporting heavy doors where the space for counterweighting is relatively small and/or it is inadvisable or impossible to use an ordinary counterweight and pulley.

The object of our invention is to provide a mechanism of the type described in which the door will be in equilibrium in any position, and in which the door may swing a considerable distance for a relatively short movement of the counterweight. A further object is to provide a counterbalanced door mechanism which will be simple, economical and effective. Other objects will be apparent from the following description By way of illustration we have shown the invention as applied to heavy doors which permit access to roof tube headers in a pipe still. The openings in front of these headers are necessarily small and there is no room for the provision of ordinary counterweights. We have provided a system of linkages whereby a slight movement of the weight corresponds to a large movement of the door and whereby the weight exactly coun-' terbalances the door in all of its positions. This system may be described as a, pivoted lever, a short arm of which forms one side of a parallelogram and the long side of which forms one arm of another parallelogram, both parallelograms consisting of pivoted lengths and having one fixed pivot in addition to the fulcrum of the lever. The invention will be more fully understood from the description of a preferred embodiment which is illustrated in the accompanying drawings wherein:

Figure 1 is a sectional elevation or a side view illustrating the system of linkages and the improved counterbalance mechanism.

Figure 2 is a front elevation of the device shown in Figure 1.

Figure 3 is a front elevation of the pipe still showing a series of counterbalanced doors, and

Figure 4 is a plan or top view of our improved device.

Our invention is applicable to any counterbalanced door, but it is particularly directed to doors which are so located that ordinary counterbalancing means cannot be employed. As an example we will describe the counterbalance doors used to cover the roof tube headers in the pipe stills used in petroleum refineries. The front wall of the pipe still is provided with an opening 11 to provide access to roof tube header 12. The roof tubes of a pipe still must be cleaned or repaired at intervals, and it is therefore necessary to provide a readily accessible header. At the front of the opening we provide a channel beam 13 which, at intervals, carries bearing lugs 14 which carry pivot pins 15. outwardly projecting lugs 16 are'pivoted on pins and are adapted to carry the heavy closure or door 17 which normally closes opening 11. At the outer end of each door we provide a pivotal bearing 18, which is engaged to one end of link 19. The other end of link 19 pivotally engages the outer (35 end 20 of the long arm of lever 21, which is pivotally mounted on a bolt 22 which is carried by brackets 23. The outer end 24 of the short arm of lever 21 pivotally engages link 25, which consists of a bail secured to bolts 26 for carrying counterweight 27. Elements 25, 26 and 27 constitute one link of our mechanism which is pivotally connected by a pivot 28 to link 29, which is, in turn, pivotally connected to fixed pivot 30.

The bracket 23 may be mounted on suitable upright angle irons 31 in the front wall of the pipe still structure. If the door is near the roof it will be necessary to provide an aperture 32 to allow free movement of the lever 21 therethrough. The roof 33 is supported by I-beam 34 on the top of side walls 35. A platform 36 is provided underneath the opening 11 so that when the door 17 is swung into its lowermost position, workmen may stand on platform 36 for cleaning or repairing tubes in header 12. I 85 Referring more particularly to the elements of our counterbalance mechanism, it should be observed that the door 17 forms one side of a parallelogram, this door being equal in length and parallel to the long arm of lever 21. In otherwords, pivots 15, 18, 20 and 22 define a parallelogram having fixed pivots at 15 and 22.

Pivots 22, 24, 28 and form another parallelogram having fixed pivots at 22 and 30. It will be noted that pivot 22 is common to both par- 5 allelograms and that the short arm and long arm of the lever are rigid with respect to each other. A line drawn from the center of gravity of door 17 to pivot 15 is always parallel to link 29 except when the door is in substantially closed position, at which time link 29 rests against the side of wall 10 and the center of gravity of the door is to the right of pivot pin 15. When the center of gravity of door 17 is directly above pivot 15, the center of gravity of weight 2'7 is directly below pivot 22. As the door is swung open its center of gravity moves to the left of pivot pin 15 and at the same time counterbalance 27 moves to the right of pivot pin 22. The relative lengths of the long and short arms of lever 21 are so proportioned that the door is in equilibrium in all positions and this is possible because of the parallel linkage system, weight 27 moving to the right of pivot 30 while the center of gravity of door 17 moves to the left of pivot pin 15. It is usually desirable to swing the door through an angle of nearly 180, which merely means that link 29 will swing through the same angle and that the door will be in equilibrium in all positions.

While we have described a preferred embodiment of our invention it is to be understood that we do not limit ourselves to the details therein set forth except as defined by the following claims:

We claim: 7

1. In a counter-balanced door mechanism, a pivoted door, a lever pivoted upon a fixed axis intermediate its length to provide relatively long and short lever arms on the opposite sides re spectively of said axis, said long lever arm being equal in length to the length of the door in a direction away from its pivotal mounting, means inter-connecting the outer end of the door and the outer end of said long lever arm, said inter-connecting means being of a length such as to maintain the lever arm in parallel relationship with said door, a counter-weight pivotally connected with outer end of said short lever arm, said weight having a mass suflicient to counter-balance the door through the lever and inter-connecting means, and a link pivotally mounted upon a fixed pivot, at one end, and pivotally connected with the counter-weight at the other end, said link being equal in length to the short lever arm.

2. In combination, a structure having an opening therein, a hinge secured to said structure adjacent to said opening, a door for closing said opening mounted upon said hinge, a pivot mounted on said structure at a point spaced from said door, a lever'comprising two lever arms mounted on said pivot, means for connecting the outerend of one lever arm with a point on said door spaced from said hinge, the distance between the door connection and the hinge being equal in length to said lever arm and the length of the connection being equal to the distance between said pivot and said hinge, a counterweight suspended from the other lever arm, said other lever arm being parallel to a line drawn from the center of gravity of said door through said hinge, and a link equal in length to said other lever arm pivoted to said counterweight and pivoted to said structure at such a point that said link will be parallel to said other lever arm. r

3. In combination, a structure having an opening therein, a hinge secured to said structure adjacent to said opening, a door for closing said opening mounted on said hinge, a pivot mounted on said structure at a point spaced from said hinge, a lever comprising two lever arms mounted on said pivot, means for connecting the outer end of one lever arm with a point on said door spaced from said hinge, the distance between the door connection and the hinge being equal in length to said lever arm and the length of the connection being equal to the distance between said pivot and said hinge, a counterweight suspended from the other lever arm, and a link equal in length to said other lever arm pivoted to said counterweight and pivoted to said structure at such a point that said link will be parallel to said other lever arm and the center of gravity of the weight will be under said pivot when the center of gravity of the door is in vertical alignment with said hinge.

4. In combination, a structure having an opening therein, a substantially horizontal hinge secured to said structure adjacent to said opening, a

- door pivotally mounted on said hinge, a counterof said counter-weight being such as to provide a condition of balance between the counter-weight and the door through said lever.

5. In combination, a structure having an opening tierein, a substantially horizontal hinge secured to said structure adjacent to said opening, a door pivotally mounted on said hinge, a counterweight located above said opening for said door, a lever having two lever arms pivoted to said structure above said door, one of said lever arms being equal in length to the length of said door, the other of said lever arms being the shorter of the two, connected to said counter-weight, and means interconnecting the outer end of the longer lever arm to the outer end of .the door, the mass of said counter-weight being such as to provide a condition of balance between the counter-weight and thedoor through said lever.

FRED W. SCHEINEMAN. BENJAMIN FRANKLIN. 

